title: Induction of apoptosis in K562 cells by dicyclohexylammonium salt of hyperforin through a mitochondrial-related pathway.
abstract: Hyperforin is an abundant phloroglucinol-type constituent isolated from the extract of the flowering upper portion of the plant Hypericum perforatum L. The dicyclohexylammonium salt of hyperforin (DCHA-HF) has exhibited antitumor and antiangiogenic activities in various cancer cells. Here, the antitumor effects of DCHA-HF on the chronic myeloid leukemia K562 cell line were investigated for the first time. DCHA-HF exhibited dose- and time-dependent inhibitory activities against K562 cells, with IC(50) values of 8.6 and 3.2 μM for 48 h and 72 h of treatment, respectively, which was more effective than that of the hyperforin. In contrast, little cytotoxic activity was observed with DCHA-HF on HUVECs. DCHA-HF treatment resulted in induction of apoptosis as evidenced from DNA fragmentation, nuclear condensation and increase of early apoptotic cells by DAPI staining analysis, TUNEL assay and Annexin V-FITC/PI double-labeled staining analysis, respectively. Moreover, DCHA-HF elicited dissipation of mitochondrial transmembrane potential that commenced with the release of cytochrome c through down-regulation of expression of anti-apoptotic proteins and up-regulation of expression of pro-apoptotic proteins. DCHA-HF treatment induced activation of the caspase 3, 8, and 9 cascade and subsequent PARP cleavage, and DCHA-HF-induced apoptosis was significantly inhibited by caspase inhibitors. Treated cells were arrested at the G1 phase of the cell cycle and the expression of p53 and p27(Kip1), two key regulators related to cell cycle and apoptosis, was up-regulated. These results suggest that DCHA-HF inhibits K562 cell growth by inducing caspase-dependent apoptosis mediated by a mitochondrial pathway and arresting the cell cycle at the G1 phase. Therefore, DCHA-HF is a potential chemotherapeutic antitumor drug for chronic myeloid leukemia therapy.
authors.affiliation: School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, PR China.
authors.forename: Jin-Yun
authors.initials: JY
authors.lastname: Liu
authors.forename: Zhong
authors.initials: Z
authors.lastname: Liu
authors.forename: Dong-Mei
authors.initials: DM
authors.lastname: Wang
authors.forename: Man-Mei
authors.initials: MM
authors.lastname: Li
authors.forename: Shao-Xiang
authors.initials: SX
authors.lastname: Wang
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Chen
authors.forename: Yi-Fei
authors.initials: YF
authors.lastname: Wang
authors.forename: De-Po
authors.initials: DP
authors.lastname: Yang
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000633:toxicity*; D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D050760:Cyclin-Dependent Kinase Inhibitor p27 / Q000378:metabolism; D045304:Cytochromes c / Q000378:metabolism; D053938:DNA Fragmentation; D016193:G1 Phase; D006801:Humans; D020902:Hypericum / Q000737:chemistry; D020014:K562 Cells; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D010696:Phloroglucinol / Q000031:analogs & derivatives / Q000737:chemistry; D015398:Signal Transduction; D013729:Terpenes / Q000737:chemistry / Q000633:toxicity*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D013729:Terpenes; D016159:Tumor Suppressor Protein p53; C559745:hyperforin dicyclohexylammonium; D050760:Cyclin-Dependent Kinase Inhibitor p27; D045304:Cytochromes c; D010696:Phloroglucinol; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; C001654:hyperforin